1. Field of the Invention
The present invention relates to a hand air pump, and more particularly to a hand air pump including a gauge device that may be easily and quickly and readily assembled to the hand air pump without additional tools and that may be easily and quickly manufactured with a decreased manufacturing fee.
2. Description of the Prior Art
Typical hand air pumps comprise a cylindrical housing or pump barrel including a chamber formed therein for slidably receiving or engaging with a piston and a piston rod therein, and a tube coupled to an air passage of the pump barrel for receiving the pressurized air from the pump barrel and for supplying the pressurized air to an air nozzle.
For example, U.S. Pat. No. 1,425,614 to Stickel, U.S. Pat. No. 2,576,687 to Krehbiel, U.S. Pat. No. 3,981,625 to Wickenberg, and U.S. Pat. No. 4,673,007 to Huang disclose several of the typical air liquid pumps each also comprising a hollow cylinder having a chamber for slidably receiving or engaging with a piston and a piston rod therein which may be moved relative to the hollow cylinder to generate a pressurized air and to supply the pressurized air to inflate various objects, such as vehicle tires, shoes, inflatable balls or the like, and further comprising a manometric gauge device for measuring or indicating the air pressure within the hollow cylinder.
However, the numerals of the graduations of the manometric gauge device are formed or provided on the outer peripheral portion of the cylinder and may not be easily and clearly seen or read by the users.
U.S. Pat. No. 3,907,461 to Bouder, and U.S. Pat. No. 6,805,537 to Wu disclose two further typical hand air pumps each comprising a manometric gauge or pressure measuring device including a screw or threaded member for assembling to or detaching from a connecting member of a hollow cylinder or pump barrel or casing.
However, the manometric gauge or pressure measuring device will be extended out of the pump barrel or casing or cylinder and may be rotated relative to the pump barrel to a position that may not be easily seen or read by the users.
U.S. Pat. No. 5,964,577 to Chuang, and U.S. Pat. No. 6,558,129 to Wang disclose two further typical hand air pumps each comprising a manometric gauge or pressure measuring device pivotally or rotatably coupled to the cylinder or pump barrel without a mount.
However, the pivotal coupling structure of the manometric gauge or pressure measuring device to the cylinder or pump barrel is complicated and may not be easily and quickly manufactured and may have a greatly increased manufacturing fee.
U.S. Pat. No. 6,485,264 to Wu discloses a still further typical hand air pump comprising a manometric gauge or pressure measuring device attached or mounted to the cylinder or pump barrel with a pressure gauge seat and an attaching member and a coupling conduit.
However, the pressure gauge seat and the attaching member and the coupling conduit are extended out of the cylinder or pump barrel and may spoil the outer appearance of the typical hand air pump.
U.S. Pat. No. 7,331,768 to Wu discloses a still further typical hand air pump comprising a manometric gauge or pressure measuring device attached or mounted to the cylinder or pump barrel with a coupling collar and a connecting tube and two or more joints.
However, the coupling collar and the connecting tube are extended out of the cylinder or pump barrel and may spoil the outer appearance of the typical hand air pump.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional gauge devices for the hand air pumps.